Your fruit isn’t so fresh. Take the apple. That one on your desk has likely been sitting in storage for months (tasty). So, to keep it looking fresh, it’s been treated with diphenylamine (DPA), a pesticide that doesn’t kill insects or fungal growths, but is designed to prevent fruit from developing brown or black patches.
This past March, the European Union issued what seemed, to many unaware of its proactive stance, like a very surprising statement. It would ban the importation of all apples containing the chemical, costing U.S apple growers $20 million in annual export sales. If Europe’s so worried, why aren’t we?
Introduced in 1962, DPA has been evaluated for safety several times, and subsequently deemed “unlikely to present a public health concern” by the World Health Organization. It does, however, have the potential to break down into carcinogenic nitrosamine after sitting on shelved apples for months post-harvest, according to a report by the Environmental Working Group. (Since the 1970s, the government has regulated products to prevent human exposure to nitrosamines.)
In a study by the pesticide’s manufacturers, researchers found three unknown chemicals on apples treated with DPA, but couldn’t determine whether any were nitrosamines. This unanswered question drove the European Commission to first ban DPA use on fruit grown within its own 28 member nations—and now to outlaw the import of any apples and pears containing more than 0.1 parts per million of DPA.
“Nobody has been able to identify any real risk from DPA, but Europe is trying to be on the prudent side,” says pesticide expert Carl Winter, a food toxicologist at the University of California–Davis. The Environmental Protection Agency, on the other hand, green-lights DPA residue of up to ten parts per million—a hundred times the new European standard.
But while Europe changed its stance, the Codex Committee on Pesticide Residues, and international regulatory group, hasn’t altered its regulations either, also setting them at ten parts per million.
Both the EPA and Codex—depending on who you ask—have consistently set careful standards for the safety of chemicals. And what we end up eating often contains much lower concentrations than the standards allow. A 2011 study by Winter’s team found that our typical exposure to DPA is 208 times lower than the established acceptable level.
Of course, there’s a catch: the EPA can license a chemical that hasn’t met all the requirements—such as those for comprehensive disease-testing—on the condition that the manufacturer follows up on its data after approval. But two separate studies from the Natural Resources Defense Council (NRDC) and the Government Accountability Office found that the EPA uses this conditional registration process more often than necessary, and doesn’t always review the follow-up data, which means pesticides have been approved without confirming that they pose no real risk.
And there are factors that the EPA overlooks. It doesn’t require testing against many of the more subtle and sensitive diseases, like hormone disruption and learning disabilities (many of which have been linked to pesticide exposure). It doesn’t account for exposure to multiple pesticides at once (such as in air and water). And it often doesn’t change regulations to reflect new studies——until that ten-year review date comes up, says Jennifer Sass, a senior scientist at the NRDC.
To ever call pesticides safe is likely a misnomer. “Pesticides are literally designed to kill organisms,” Sass points out. “What the EPA regulates is safety when used according to the label, not safety against all human diseases and effects.”
Unfortunately for consumers, while there’s a handful of studies suggesting that pesticide exposure can increase the risk of birth defects, respiratory illnesses, and cancer, there are far fewer studies analyzing the effect of merely eating chemical-covered produce.
A 2011 British meta-analysis did find that organic produce has slightly more vitamins and antioxidants than chemical-covered versions (though some studies have shown otherwise), and a 2013 study in PLoS ONE revealed that fruit flies live longer when fed extracts from organic, rather than conventional, produce. But, explains Sass, exposure levels are too low, and people too diverse, for us to really test the health effects of eating organic fruit and vegetables alone.
Back to the big question: should the U.S. follow in the EU’s footsteps? Possibly. Many Americans—including the EWG—believe Europe’s decision should prompt the EPA to revisit the pesticide’s safety. But, as Winter explains, since all growers outside Europe follow the international standard of ten parts per million, doing so would have a huge impact on international trade.
Regardless of the U.S.’s actions, do keep eating those apples. “The health benefits of consuming fruits and vegetables far outweigh any potential risks from these chemicals,” says Ruth MacDonald, a registered dietitian who chairs the Food Science and Human Nutrition department at Iowa State University. If you have the financial means and the drive to buy organic, go for it—but don’t stop eating apples just because they have pesticides on them.